ML320 Emissions, Mass Air, Adaptatio-success
 

My '99 ML320 failed WA emissions which simply reads fault codes for late model vehicles. The fault codes PO170 and PO173, both banks, showed. I disconnected the battery for 15 minutes, reconnected, and the codes were cleared long enough to pass the test. The car now had little power past 4000 rpm so I took the tape off the check engine light and found it had gone back on. A suggestion was made the I had lost pre component failure adaptation and would not get it back till I replaced the component. An internet search disclosed Brotherton's 6/2004 Import Car article implicating the Mass Air Sensor. Cleaning with tuner cleaner and more aggressive solvents was ineffective so I conducted an internet used part search and found the device out of a 27,000 mile E-class from HW 75 Auto Salvage in Georgetown MN for $95 (no freight charge for this $275-$375 item). This fixed the problem and the computer fine tuned itself w/o hundreds of dollars worth of shop "adaptation." In the process of analyzing this problem, I had a one hour Star computer diagnosis done by an independent shop which was inconclusive but only cost $75 with the $50 off coupon I got for my new business. The Star Computer does not seem to be the magic diagnostic tool I had hoped for. Our state law requires a written estimate for repairs over $100 and this provided corroboration of Brotherton's opinion. The best approach to a MB problem looks like getting a written estimate from the local
dealer and buying a used component on-line. Adaptation is not required for a venicle built for world wide use especially when the manual notes that most faults are reexamined by the computer every few days.